Iron surface determinant B (IsdB) (IsdB)

Iron surface determinant B (IsdB) is a cell wall-anchored surface protein in Staphylococcus aureus that is essential for bacterial iron acquisition during infection (UniProt, 2024). It specifically binds to human hemoglobin via its NEAT (NEAr Transporter) domains and extracts the heme moiety, which is then transferred to other Isd proteins for transport into the cytoplasm (PubMed, 2011). As iron is a limiting factor for bacterial growth in the host, IsdB is considered a high-priority therapeutic target for vaccines and passive immunization (NIH, 2023). The most notable clinical candidate was the V710 vaccine, which aimed to induce opsonophagocytic antibodies to clear the pathogen (JAMA, 2013). However, a large-scale Phase II/III trial was halted due to safety concerns, specifically an increased risk of death and multi-organ failure in vaccine recipients who developed S. aureus infections (Fowler et al., 2013). Current research continues to explore IsdB's structural biology to design safer immunogens or small-molecule inhibitors that block heme uptake.

Other names

Heme-binding protein IsdBHemoglobin-binding protein IsdBStaphylococcus aureus IsdB

Induction of active immunity through the production of antibodies that block hemoglobin binding and promote opsonophagocytic killing of Staphylococcus aureus.